Slip-layered catheter balloon

Abstract

A slip-layered balloon catheter for insertion into a bodily conduit, especially an artery. The catheter comprises a shaft (21) having at least one lumen (26) for delivery of a fluid inflation media and a slip-layered balloon (12) made up of a plurality of layers with a low-friction substance between the layers. The low-friction substance causes the layers to slide readily relative to one another, softening the balloon while maintaining its strength. Optionally, the balloon includes a plurality of slip-layered segments radially disposed about the balloon wall, and separated by lengthwise ridges joining the layers of each segment together. Also optionally, an elastic sleeve surrounds the balloon wall to improve refoldability of the balloon.

We claim: 
     
       1. A soft, pliable, inflatable and refoldable slip-layered balloon for use with a medical catheter device, said balloon comprising a wall defining a chamber, said wall comprising at least two imperforate coextensive layers of a non-compliant polymeric medical balloon material, said layers having therebetween a low-friction substance imparting a low coefficient of friction between facing surfaces of said layers, such that said layers become slip-layers which readily slide with respect to one another as said balloon is inflated and deflated. 
     
     
       2. A balloon in accordance with claim 1 wherein said balloon wall comprises at least three layers of said medical balloon material having therebetween said low-friction substance. 
     
     
       3. A balloon in accordance with claim 1 wherein said low-friction substance comprises silicone. 
     
     
       4. A balloon in accordance with claim 1 wherein said balloon wall comprises a generally cylindrical central portion between tapered proximal and distal end portions. 
     
     
       5. A balloon-in accordance with claim 1 wherein said balloon wall is unitary, said layers being joined to one another at a plurality of ridges, each of said ridges extending the full axial length of said wall and being separated from others of said ridges by slip-layered segments extending the full axial length of said wall and in which said layers become slip-layers which readily slide with respect to one another as said balloon is inflated and deflated. 
     
     
       6. A balloon in accordance with claim 1 further comprising an elastomeric sleeve surrounding and coextensive with said wall to aid in refolding said balloon as said balloon is deflated. 
     
     
       7. A balloon in accordance with claim 6 further comprising, between said elastomer sleeve and the outermost of said layers, said low-friction substance, such that a low coefficient of friction is imparted between facing surfaces of said elastomer sleeve and said outermost layer and such that said elastomer sleeve and said outermost layer also become slip-layers which readily slide with respect to one another as said balloon is inflated and deflated. 
     
     
       8. A balloon in accordance with claim 1 wherein said balloon has a fully inflated diameter of about 0.04-2 inches, a deflated, folded profile diameter of about 0.03-0.25 inches, and a layer thickness of about 0.0001-0.004 inches. 
     
     
       9. A soft, pliable, inflatable and refoldable slip-layered balloon for use with a medical catheter device, said balloon comprising a unitary wall defining a chamber, said wall comprising at least two imperforate coextensive layers of a non-compliant polymeric medical balloon material joined to one another at a plurality of ridges, each of said ridges extending the full axial length of said wall and being separated from others of said ridges by slip-layered segments extending the full axial length of said wall and in which said layers have therebetween a low-friction substance imparting a low coefficient of friction between facing surfaces of said layers, such that said layers become slip-layers which readily slide with respect to one another as said balloon is inflated and deflated. 
     
     
       10. A balloon in accordance with claim 9 further comprising an elastomer sleeve surrounding and coextensive with said wall, and further comprising, between said elastomer sleeve and the outermost of said layers, said low-friction substance, such that a low coefficient of friction is imparted between facing surfaces of said elastomer sleeve and said outermost layer and such that said elastomer sleeve and said outermost layer also become slip-layers which readily slide with respect to one another as said balloon is inflated and deflated. 
     
     
       11. A catheter for insertion into a bodily conduit, said catheter comprising: a shaft comprising a lumen for delivery of fluid inflation media,   a soft, pliable, inflatable and refoldable balloon having a wall concentric with said shaft and defining a chamber, said chamber being in fluid communication with said lumen for inflation of said balloon, wherein said wall comprises at least two imperforate coextensive non-adhering layers of a non-compliant polymeric medical balloon material, said layers having therebetween a low-friction substance imparting a low coefficient of friction between facing surfaces of said layers, such that said layers become slip-layers which readily slide with respect to one another as said balloon is inflated and deflated.   
     
     
       12. A method for fabricating a soft, pliable, inflatable and refoldable slip-layered balloon for use with a medical catheter device, said method comprising the steps of: providing on a first imperforate layer of a non-compliant medical balloon material at least one imperforate coextensive additional layer to form a balloon wall comprising at least two layers of a non-compliant medical balloon material, said wall defining a chamber;   disposing between said layers a low-friction substance imparting a low coefficient of friction between facing surfaces of said layers, such that said layers become slip-layers which readily slide with respect to one another as said balloon is inflated and deflated.   
     
     
       13. A method in accordance with claim 12 wherein said step of providing said at least one additional layer on said first layer comprises extruding said medical balloon material to form said first layer and said at least one additional layer of said balloon wall. 
     
     
       14. A method for fabricating a slip-layered balloon for use with a medical catheter device, said method comprising the steps of: coextruding a polymeric medical balloon material and a second polymeric material such that said medical balloon material forms a continuous phase providing a generally tubular balloon blank and said second material forms a discrete phase surrounded by said continuous phase and providing strands extending lengthwise within said blank;   removing said strands from said blank;   shaping said strand-removed blank to form a balloon comprising a unitary wall defining a chamber, said wall comprising at least two layers of a said medical balloon material joined to one another at a plurality of ridges, each of said ridges extending the length of said wall and being separated from others of said ridges by layered segments of said wall; and   disposing between said layers of said segments a low-friction substance imparting a low coefficient of friction between facing surfaces of said layers, such that said layers become slip-layers which readily slide with respect to one another as said balloon is inflated and deflated.   
     
     
       15. A method in accordance with claim 14 wherein said second material is softer than said medical balloon material, and wherein said strand removing step comprises: scoring said balloon blank to form a score-line in the circumferential direction along the outermost surface of said medical balloon material near an end of said blank, without affecting said second material;   breaking said medical balloon material at said score-line to separate said medical balloon material of said end from the remainder of said medical balloon material;   removing said separated medical balloon material from said blank by pulling said separated medical balloon material off of said strands, thereby exposing an end of each of said strands; and   gripping and pulling on said strand ends to remove said strands from said blank.